Polymerization catalyst, production and use

ABSTRACT

Ethylene and alpha-olefins are homopolymerized or copolymerized with another olefin monomer in the presence of a catalyst system comprising an organo metal cocatalyst and a titanium-containing catalyst component, said titanium-containing catalyst component being obtained by reacting together a porous particulate material, an organic magnesium compound, an oxygen containing compound, an acyl halide and titanium tetrachloride and a Group IIIa hydrocarbyl metal dihalide and prepolymerizing the solid with a minor amount of ethylene.

BACKGROUND OF THE INVENTION

This invention relates to a novel catalyst component to be employed witha cocatalyst for use in the polymerization of olefins to polyolefinssuch as polyethylene, polypropylene and copolymers such as ethylenecopolymers with other alpha-olefins and diolefins. The catalyst isespecially useful for the production of linear low density and highdensity polyethylenes, which catalyst component shows unusually highactivity and excellent hydrogen response for the control of polymermolecular weight while obtaining improved comonomer response andimproved bulk density of produced polymer product. The polymer productobtained evidences an important balance of polymer properties, forexample, the catalyst system obtains a polymer with a high bulk density,narrow molecular weight distribution, an improved balance in polymerproduct machine direction tear strength and transverse direction tearstrength. As a result, blown film produced from polymer products such aslinear low density polyethylene manifests an overall higher strength.

The catalyst component comprises a prepolymerized solid reaction productobtained by contacting a solid, particulate, porous support materialsuch as, for example, silica, alumina, magnesia or mixtures thereof, forexample, silica-alumina, in stages with an organometallic compositiontreated with an oxygen containing compound, an acyl halide, a transitionmetal compound, a Group IIIa metal hydrocarbyl dihalide andprepolymerizing the solid product with ethylene to form a prepolymerizedtransition metal catalyst component. The novel catalyst component, whichwhen used with an aluminum alkyl cocatalyst, provides the novel catalystsystem of this invention which can be usefully employed for thepolymerization of olefins.

The catalyst system can be employed in slurry, single-phase melt,solution and gas-phase polymerization processes and is particularlyeffective for the production of linear polyethylenes such as highdensity polyethylene.

Recently, interest has arisen in the use of magnesium-titanium complexcatalyst components for the polymerization of olefins. For example,European Patent Application No. 27733, published Apr. 29, 1981 disclosesa catalyst component obtained by reducing a transition metal compoundwith an excess of organomagnesium compound in the presence of a supportsuch as silica and thereafter deactivating the excess organomagnesiumcompound with certain deactivators including hydrogen chloride.

U.S. Pat. No. 4,136,058 discloses a catalyst component comprising anorganomagnesium compound and a transition metal halide compound, whichcatalyst component is thereafter deactivated with a deactivating agentsuch as hydrogen chloride. This patent does not teach the use of supportmaterial such as silica but otherwise the disclosure is similar to theabove-discussed European patent application.

U.S. Pat. No. 4,250,288 discloses a catalyst which is the reactionproduct of a transition metal compound, an organomagnesium component andan active non-metallic halide such as HCl and organic halides containinga labile halogen. The catalyst reaction product also contains somealuminum alkyls.

Catalyst components comprising the reaction product of an aluminumalkyl-magnesium alkyl complex plus titanium halide are disclosed in U.S.Pat. No. 4,004,071 and U.S. Pat. No. 4,276,191.

U.S. Pat. No. 4,173,547 and U.S. Pat. No. 4,263,171, respectivelydisclose a catalyst component comprising silica, an organoaluminumcompound, titanium tetrachloride and dibutyl magnesium and a catalystcomponent comprising a magnesium alkyl-aluminum alkyl complex plustitanium halide on a silica support.

Each of U.S. Pat. Nos. 4,402,861, 4,378,304, 4,388,220, 4,301,029 and4,385,161 disclose supported catalyst systems comprising an oxidesupport such as silica, an organomagnesium compound, a transition metalcompound and one or more catalyst component modifiers. These patents donot disclose the catalysts of this invention.

In British Pat. No. 2,101,610 silica is treated with a magnesium alkyl,an alcohol, benzoyl chloride and TiCl₄. In each of Japanese Kokai Nos.50-098206 and 57-070107 acyl halides are employed during the preparationof titanium supported catalysts.

The catalyst systems comprising magnesium alkyls and titanium compounds,although useful for the polymerization of olefins such as ethylene andother 1-olefins, often do not show excellent responsiveness to hydrogenduring the polymerization reaction for the control of molecular weight,do not show an extremely high catalytic activity and obtain polymerproduct manifesting poor bulk density and film properties.

Prepolymerization of Ziegler-type catalysts are illustrated in BritishPat. No. 1,300,734, U.S. Pat. No. 3,404,096, U.S. Pat. No. 3,689,597 andU.S. Pat. No. 4,177,160. These patents do not disclose improving polymerbulk density by way of prepolymerizing a supported catalyst with a minoramount of ethylene.

In U.S. Pat. No. 4,451,574 issued May 29, 1984 a catalyst systemobtained by treating an inert particulate support, such as silica, withan organometallic compound such as a magnesium alkyl, a titanium halideand a halogen gas is disclosed. Although the catalyst obtains very highactivities, there is a need for improving the film properties of polymerproduct obtained by polymerizing olefins in the presence of the catalystand to improve the bulk density of polymer product.

In my cofiled application Ser. No. 638,168, filed Aug. 6, 1984, now U.S.Pat. No. 4,558,025 there is disclosed a titanium containing catalystcomponent obtained by treating an inert particulate support such assilica with the reaction product of magnesium dialkyl and an alcohol, anacyl halide, a transition metal compound such as titanium tetrachlorideand a Group IIIa metal alkyl dihalide.

In accordance with this invention catalyst combinations have been foundwhich have extremely high catalytic activities and excellent hydrogenresponsiveness for the control of molecular weight and obtain polymerproduct with greatly improved film properties and bulk density. Theresins exhibit excellent melt strength with a surprising decrease inpower consumption hence an increase in extrusion rates, excellent MDtear strength and dart impact strength.

The new catalyst systems and catalyst component of this invention areobtained by contacting an organometallic compound, an alcohol, an acylhalide, a transition metal compound and a Group IIIa metal hydrocarbyldihalide in the presence of an oxide support and prepolymerizing with aminor amount of ethylene. The catalyst system employing the transitionmetal containing catalyst component is advantageously employed in a gasphase ethylene polymerization process since there is a significantdecrease in reactor fouling as generally compared with catalytic priorart ethylene gas phase polymerization processes thereby resulting inless frequent reactor shut downs for cleaning.

SUMMARY OF THE INVENTION

In accordance with the objectives of this invention there is provided atransition metal containing catalyst component for the polymerization ofalpha-olefins comprising a prepolymerized solid reaction productobtained by treating an inert solid support material in an inert solventsequentially with (A) an organometallic compound of a Group IIa, IIb orIIIa metal of the Periodic Table wherein all the metal valencies aresatisfied with a hydrocarbon or substituted hydrocarbon group, (B) anoxygen containing compound selected from ketones, aldehydes, alcohols,siloxanes or mixtures thereof, (C) an acyl halide, (D) at least onetransition metal compound of a Group IVb, Vb, VIb or VIII metal of thePeriodic Table, and (E) a Group IIIa metal hydrocarbyl dihalide andprepolymerizing the transition metal containing solid with a minoramount of ethylene with the proviso that the inert solid supportmaterial can be treated alternatively with (i) the (A) organometalliccompound and the (B) oxygen containing compound simultaneously, (ii) thereaction product of the (A) organometallic compound and (B) oxygencontaining compound or (iii) the (B) oxygen containing compound followedby treating with the (A) organometallic compound. The olefin employedfor prepolymerization is ethylene.

The solid transition metal containing catalyst component when employedin combination with a cocatalyst such as an alkyl aluminum cocatalystprovides a catalyst system which demonstrates a number of uniqueproperties that are of great importance in the olefin polymerizationtechnology such as, for example, extremely high catalytic activity, theability to control the molecular weight during the polymerizationreaction as a result of the improved responsiveness to hydrogen,increased polymer yield, improved comonomer response and significantincrease in catalytic activity as well as producing resin of reducedaverage particle size as compared with the non-prepolymerized catalystdescribed in my copending application Ser. No. 638,168 filed Aug. 6,1984, U.S. Pat. No. 4,558,025. The polymer product obtained from thepolymerization of olefins and particularly ethylene manifests improvedbulk density, melt strength and tear strength.

In a preferred embodiment of the invention the (A) organometalliccompound is a dihydrocarbon magnesium compound represented by R¹ MgR²wherein R¹ and R² which can be the same or different are selected fromalkyl groups, aryl groups, cycloalkyl groups, aralkyl groups, alkadienylgroups or alkenyl groups having from 1 to 20 carbon atoms, the (B)oxygen containing compounds are selected from alcohols and ketonesrepresented by the formula R³ OH and wherein R³ and each of R⁴ and R⁵which may be the same or different can be an alkyl group, aryl group,cycloalkyl group, aralkyl group, alkadienyl group or alkenyl grouphaving from 1 to 20 carbon atoms, the (D) transition metal compound ispreferably a transition metal compound or combination of transitionmetal compounds represented by the formulas TrX'_(4-q) (OR⁶)q,TrX'_(4-q) R_(q) ⁷, VO(OR⁶)₃ and VOX'₃ wherein Tr is a transition metalof Groups IVb, Vb, VIb, VIIb and VIII and preferably titanium, vanadiumor zirconium, R⁶ is an alkyl group, aryl group, aralkyl group,substituted aralkyl group having from 1 to 20 carbon atoms and1,3-cyclopentadienyls, X' is halogen and q is zero or a number less thanor equal to 4, and R⁷ is an alkyl group, aryl group or aralkyl grouphaving from 1-20 carbon atoms or a 1,3-cyclopentadienyl. In aparticularly preferred embodiment of the invention the (A)organometallic compound and the (B) oxygen containing compound arereacted together prior to contact with the inert support.

All references to the Periodic Table are to the Periodic Table of theElements printed on page B-3 of the 56th Edition of Handbook ofChemistry and Physics, CRC Press (1975).

In a second embodiment of this invention there is provided a catalystsystem comprising the transition metal containing solid catalystcomponent and an organoaluminum cocatalyst for the polymerization ofalpha-olefins using the catalyst of this invention under conditionscharacteristic of Ziegler polymerization.

In view of the high activity of the catalyst system prepared inaccordance with this invention as compared with conventional Zieglercatalysts, it is generally not necessary to deash polymer product sincepolymer product will generally contain lower amounts of catalystresidues than polymer product produced in the presence of conventionalcatalyst.

The catalyst systems can be employed in a gas phase process, singlephase melt process, solvent process or slurry process. The catalystsystem is usefully employed in the polymerization of ethylene and otheralpha-olefins, particularly alpha-olefins having from 3 to 8 carbonatoms and copolymerization of these with other 1-olefins or diolefinshaving from 2 to 20 carbon atoms, such as propylene, butene, pentene andhexene, butadiene, 1,4-pentadiene and the like so as to form copolymersof low and medium densities. The supported catalyst system isparticularly useful for the polymerization of ethylene andcopolymerization of ethylene with other alpha-olefins in gas phaseprocesses.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Briefly, the catalyst components of the present invention comprise theethylene prepolymerized solid reaction product of (A) an organometalliccomposition, (B) an oxygen containing compound, (C) an acyl halide and(D) at least one transition metal compound in the presence of an oxidesupport material. According to the polymerization process of thisinvention, ethylene, at least one alpha-olefin having 3 or more carbonatoms or ethylene and other olefins or diolefins having terminalunsaturation are contacted with the catalyst under polymerizingconditions to form a commercially useful polymeric product. Typically,the support can be any of the solid particulate porous supports such astalc, zirconia, thoria, magnesia, and titania. Preferably the supportmaterial is a Group IIa, IIIa, IVa and IVb metal oxide in finely dividedform.

Suitable inorganic oxide materials which are desirably employed inaccordance with this invention include silica, alumina, andsilica-alumina and mixtures thereof. Other inorganic oxides that may beemployed either alone or in combination with the silica, alumina orsilica-alumina are magnesia, titania, zirconia, and the like. Othersuitable support materials, however, can be employed. For example,finely divided polyolefins such as finely divided polyethylene.

The metal oxides generally contain acidic surface hydroxyl groups whichwill react with the organometallic composition or transition metalcompound first added to the reaction solvent. Prior to use, theinorganic oxide support is dehydrated, i.e., subject to a thermaltreatment in order to remove water and reduce the concentration of thesurface hydroxyl groups. The treatment is carried out in vacuum or whilepurging with a dry inert gas such as nitrogen at a temperature of about100° to about 1000° C., and preferably from about 300° C. to about 800°C. Pressure considerations are not critical. The duration of the thermaltreatment can be from about 1 to about 24 hours. However, shorter orlonger times can be employed provided equilibrium is established withthe surface hydroxyl groups.

Chemical dehydration as an alternative method of dehydration of themetal oxide support material can advantageously be employed. Chemicaldehydration converts all water and hydroxyl groups on the oxide surfaceto inert species. Useful chemical agents are, for example, SiCl₄,chlorosilanes, silylamines and the like. The chemical dehydration isaccomplished by slurrying the inorganic particulate material, such as,for example, silica in an inert low boiling hydrocarbon, such as, forexample, heptane. During the chemical dehydration reaction, the silicashould be maintained in a moisture and oxygen-free atmosphere. To thesilica slurry is then added a low boiling inert hydrocarbon solution ofthe chemical dehydrating agent, such as, for example,dichlorodimethylsilane. The solution is added slowly to the slurry. Thetemperature ranges during chemical dehydration reaction can be fromabout 25° C. to about 120° C., however, higher and lower temperaturescan be employed. Preferably the temperature will be about 50° C. toabout 70° C. The chemical dehydration procedure should be allowed toproceed until all the moisture is removed from the particulate supportmaterial, as indicated by cessation of gas evolution. Normally, thechemical dehydration reaction will be allowed to proceed from about 30minutes to about 16 hours, preferably 1 to 5 hours. Upon completion ofthe chemical dehydration, the solid particulate material is filteredunder a nitrogen atmosphere and washed one or more times with a dry,oxygen-free inert hydrocarbon solvent. The wash solvents, as well as thediluents employed to form the slurry and the solution of chemicaldehydrating agent, can be any suitable inert hydrocarbon. Illustrativeof such hydrocarbons are heptane, hexane, toluene, isopentane and thelike.

The preferred (A) organometallic compounds employed in this inventionare the inert hydrocarbon soluble organomagnesium compounds representedby the formula R¹ MgR² wherein each or R¹ and R² which may be the sameor different are alkyl groups, aryl groups, cycloalkyl groups, aralkylgroups, alkadienyl groups or alkenyl groups. The hydrocarbon groups R¹or R² can contain between 1 and 20 carbon atoms and preferably from 1 toabout 10 carbon atoms. Illustrative but non-limiting examples ofmagnesium compounds which may be suitably employed in accordance withthe invention are dialkylmagnesiums such as diethylmagnesium,dipropylmagnesium, di-isopropylmagnesium, di-n-butylmagnesium,di-isobutylmagnesium, diamylmagnesium, dioctylmagnesium,di-n-hexylmagnesium, didecylmagnesium, and didodecylmagnesium;dicycloalkylmagnesium, such as dicyclohexylmagnesium; diarylmagnesiumssuch as dibenzylmagnesium, ditiolylmagnesium and dixylylmagnesium.

Preferably the organomagnesium compounds will have from 1 to 6 carbonatoms and most preferably R¹ and R² are different. Illustrative examplesare ethylpropylmagnesium, ethyl-n-butylmagnesium, amylhexylmagnesium,n-butyl-s-butylmagnesium, and the like. Mixtures of hydrocarbylmagnesium compounds may be suitably employed such as for example dibutylmagnesium and ethyl-n-butyl magnesium.

The magnesium hydrocarbyl compounds are as generally obtained fromcommercial sources as mixtures of the magnesium hydrocarbon compoundswith a minor amount of an aluminum hydrocarbyl compound. The minoramount of aluminum hydrocarbyl is present in order to facilitatesolubilization of the organomagnesium compound in a hydrocarbon solvent.The hydrocarbon solvent usefully employed for the organomagnesium can beany of the well known hydrocarbon liquids, for example hexane, heptane,octane, decane, dodecane, or mixtures thereof; aromatic hydrocarbonshaving 6 to 12 carbon atoms such as benzene, toluene, o-xylene,ethylbenzene and the like.

The organomagnesium complex with a minor amount of aluminum alkyl can berepresented by the formula (R¹ MgR²)_(p) (R₃ ⁶ Al)_(s) wherein R¹ and R²are defined as above, R⁶ has the same definition as R¹ and R², p isgreater than 0, and the ratio of s/s+p is from 0 to 1, preferably from 0to about 0.7 and most desirably from about 0 to 0.1.

Illustrative examples of the magnesium aluminum complexes are [(n-C₄H₉)(C₂ H₅)Mg][(C₂ H₅)₃ Al ]₀.02, [(nC₄ H₉)₂ Mg][(C₂ H₅)₃ Al]₀.013, [(nC₄H₉)₂ Mg][(C₂ H₅)₃ Al]₂.0 and [(nC₆ H₁₃)₂ Mg][(C₂ H₅)₃ Al]₀.01. Asuitable magnesium aluminum complex is Magala® manufactured by TexasAlkyls, Inc.

The hydrocarbon soluble organometallic compositions are known materialsand can be prepared by conventional methods. One such method involves,for example, the addition of an appropriate aluminum alkyl to a soliddialkyl magnesium in the presence of an inert hydrocarbon solvent. Theorganomagnesium-organoaluminum complexes are, for example, described inU.S. Pat. No. 3,737,393 and 4,004,071 which are incorporated herein byreference. However, any other suitable method for preparation oforganometallic compounds can be suitably employed.

The oxygen containing compounds which may be usefully employed inaccordance with this invention are alcohols, aldehydes, siloxanes, andketones. Preferably the oxygen containing compounds are selected fromalcohols and ketones represented by the formulas R³ OH and wherein R³and each or R⁴ and R⁵ which may be the same or different can be alkylgroups, aryl groups, cycloalkyl groups, aralkyl groups, alkadienylgroups, or alkenyl groups having from 2 to 20 carbon atoms. Preferablythe R groups will have from 2 to 10 carbon atoms. Most preferably the Rgroups are alkyl groups and will have from 2 to 6 carbon atoms.Illustrative examples of alcohols which may be usefully employed inaccordance with this invention are methanol, ethanol, isopropanol,1-butanol, t-butanol, 2-methyl-1-pentanol, 1-pentanol, 1-dodecanol,cyclobutanol, benzyl alcohol, and the like; diols, such as1,6-hexanediol, and the like with the proviso that the diol be contactedwith the magnesium compound subsequent to the magnesium compoundtreatment of the support material Most preferably the alcohol willcontain from 1 to 4 carbon atoms. The most preferred alcohol is1-butanol.

The ketones will preferably have from 3 to 11 carbon atoms. Illustrativeketones are methyl ketone, ethyl ketone, propyl ketone, n-butyl ketoneand the like. Acetone is the ketone of choice.

Illustrative of the aldehydes which may be usefully employed in thepreparation of the organomagnesium compound include formaldehyde,acetaldehyde, propionaldehyde, butanal, pentanal, hexanal, heptanal,octanal, 2-methylpropanal, 3-methylbutanal, acrolein, crotonaldehyde,benzaldehyde, phenylacetaldehyde, o-tolualdehyde, m-tolualdehyde, andp-tolualdehyde.

Illustrative of the siloxanes which may be usefully employed in thepreparation of the organomagnesium compound includehexamethyldisiloxane, octamethyltrisiloxane,octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,sym-dihydrotetramethyldisiloxane, pentamethyltrihydrotrisiloxane,methylhydrocyclotetrasiloxane, both linear and branchedpolydimethylsiloxanes, polymethylhydrosiloxanes,polyethylhydrosiloxanes, polymethylethylsiloxanes,polymethyloctylsiloxanes, and polyphenylhydrosiloxanes.

Any of the acyl halides may be usefully employed in accordance with thisinvention. The hydrocarbon portion of the acyl halides which can havefrom 1-20 carbon atoms can be an alkyl group, substituted alkyl group,aryl group, substituted aryl group, cycloalkyl group, alkadienyl groupor alkenyl group.

The preferred acyl halides can be represented by the formula R⁸ COXwherein R⁸ can be C₁ to C₂₀ alkyl group, substituted alkyl group, arylgroup, substituted aryl group, or cycloalkyl group and X is a halogen.The preferred halogen is chlorine.

Illustrative but non-limiting examples of the acyl halides which can beemployed in this invention are acetyl chloride, propanoyl chloride,butyryl chloride, butyryl bromide, isobutyryl chloride, benzoylchloride, oleoyl chloride, acryloyl chloride, 6-hepteneoyl chloride,heptanoyl chloride, cyclohexanecarbonyl chloride, cyclopentanepropionylchloride and the like. Acid chlorides based on polyacids may alsousefully be employed such as, for example, dodecanedioyl, succinylchloride, camphoryl chloride, terephtalloyl chloride and the like. Thepreferred acid halides are acetyl chloride, benzoyl chloride, andp-methylbenzoyl chloride.

The transition metal compounds which can be usefully employed in thepreparation of the transition metal containing catalyst component ofthis invention are well known in the art. The transition metals whichcan be employed in accordance with this invention may be represented bythe formulas TrX'_(4-q) (OR₆)q, TrX'_(4-q) R_(q), VOX'₃ and VO(OR₆)₃. Tris a Group IVb, Vb, VIb, VIIb, and VIII metal, preferably Group IVb andVb metals and preferably titanium, vanadium or zirconium, q is 0 or anumber equal to or less than 4, X' halogen, R⁶ is a hydrocarbyl orsubstituted hydrocarbyl group, for example, alkyl, aryl or cycloalkylhaving from 1 to 20 carbon atoms and R⁷ is an alkyl group, aryl group,aralkyl group, substituted aralkyl group, 1,3-cyclopentadienyls and thelike. The alkyl, aryl, aralkyls and substituted aralkyls contain from 1to 20 carbon atoms preferably 1 to 10 carbon atoms. Mixtures of thetransition metal compounds can be employed if desired.

Illustrative examples of the transition metal compounds include: TiCl₄,TiBr₄, Ti(OCH₃)₃ Cl, Ti(OC₂ H₅)Cl₃, Ti(OC₄ H₉)₃ Cl, Ti(OC₃ H₇)₂ Cl₂,Ti(OC₆ H₁₃)₂ Cl₂, Ti(OC₈ H₁₇)₂ Br₂, and Ti(OC₁₂ H₂₅)Cl₃.

As indicated above, mixtures of the transition metal compounds may beusefully employed, no restriction being imposed on the number oftransition metal compounds which may be reacted with the organometalliccomposition. Any halogenide and alkoxide transition metal compound ormixtures thereof can be usefully employed. The titahium tetrahalides areespecially preferred with titanium tetrachloride being most preferred.

The Group III hydrocarbyl dihalides are at least employed in the laststep of the transition metal containing catalyst component. Preferablythe Group III metal hydrocarbyl dihalides are selected from the boronand aluminum alkyl dihalides. The alkyl group can have from 1 to 12carbon atoms.

Illustrative, but non-limiting examples of the Group III metal alkylhalides are methyl aluminum dichloride, ethyl aluminum dichloride,propyl aluminum dichloride, butyl aluminum dichloride, isobutyl aluminumdichloride, pentyl aluminum dichloride, neopentyl aluminum dichloride,hexyl aluminum dichloride, octyl aluminum dichloride, decyl aluminumdichloride, dodecyl aluminum dichloride, methyl boron dichloride, ethylboron dichloride, propyl boron dichloride, butyl boron dichloride,isobutyl boron dichloride, pentyl boron dichloride, neopentyl borondichloride, hexyl boron dichloride, octyl boron dichloride, decyl borondichloride and the like. The preferred Group III metal alkyl dihalidesare ethyl aluminum dichloride and ethyl boron dichloride. Preferably,the treatment with the Group III metal hydrocarbyl dihalide will be fromabout 4 hours to 16 hours, however, greater or lesser times can beemployed.

The treatment of the support material as mentioned above is conducted inan inert solvent. The inert solvents can also be usefully employed todissolve the individual ingredients prior to the treatment step.Preferred solvents include mineral oils and the various hydrocarbonswhich are liquid at reaction temperatures and in which the individualingredients are soluble. Illustrative examples of useful solventsinclude the alkanes such as pentane, isopentane, hexane, heptane, octaneand nonane; cycloalkanes such as cyclopentane, cyclohexane; andaromatics such as benzene, toluene, ethylbenzene and diethylbenzene. Theamount of solvent to be employed is not critical. Nevertheless, theamount should be employed so as to provide adequate heat transfer awayfrom the catalyst components during reaction and to permit good mixing.

The organometallic component employed in step (A) either as theorganometallic compound or its reaction product with an alcohol ispreferably added to the inert solvent in the form of a solution.Preferred solvents for the organometallic compositions are the alkanessuch as hexane, heptane, octane and the like. However, the same solventas employed for the inert particulate support material can be employedfor dissolving the organometallic composition. The concentration of theorganometallic composition in the solvent is not critical and is limitedonly by handling needs.

The amounts of materials usefully employed in the solid catalystcomponent can vary over a wide range. The concentration of magnesiumdeposited on the essentially dry, inert support can be in the range fromabout 0.1 to about 2.5 millimoles/g of support, however, greater orlesser amounts can be usefully employed. Preferably, the organomagnesium compound concentration is in the range of 0.5 to 2.0millimoles/g of support and more preferably in the range of 1.0 to 1.8millimoles/g of support. The magnesium to oxygen-containing compoundmole ratio can range from about 0.01 to about 2.0. Preferably, the ratiois in the range 0.5 to 1.5, and more preferably in the range 0.8 to 1.2.The upper limit on this range is dependent on the choice ofoxygen-containing compound and the mode of addition When theoxygen-containing compound is not premixed with the magnesium compound,that is, when it is added to the support before the magnesium compoundor after the magnesium compound, the ratio may range from 0.01 to 2.0.When premixed with the organomagnesium compound, the hydrocarbyl groupson the oxygen-containing compound must be sufficiently large to insuresolubility of the reaction product. Otherwise the ratio ofoxygen-containing compound to organomagnesium compound ranges from 0.01to 1.0, most preferably 0.8 to 1.0. The amount of acyl halide employedshould be such to provide a mole ratio of about 0.1 to about 10 andpreferably 0.5 to about 2.5 with respect to the magnesium compound.Preferably the mole ratio will be from about 1 to about 2. The GroupIIIa metal hydrocarbyl dihalide employed can be in the range of about0.1 to about 10 millimoles per mole of magnesium compound with apreferred range of 0.5 to 5.0. The transition metal compound is added tothe inert support at a concentration of about 0.01 to about 1.5millimoles Ti/g of dried support, preferably in the range of about 0.05to about 1.0 millimoles Ti/g of dried support and especially in therange of about 0.1 to 0.8 millimoles Ti/g of dried support.

The prepolymerization of transition metal containing solid can beaccomplished by adding the desired amount of ethylene to the solid inthe mother-liquor without the addition of a Ziegler-type polymerizationcocatalyst. Alternatively, the solid can be recovered by means wellknown in the art such as decantation, filtration and the like, washed,returned to the mother-liquor or new diluent and then prepolymerized.

The amount of ethylene employed will be such as to provide catalystparticles containing from 0.01 to 1 weight % polymer. The prepolymerizedcatalyst particles obtained are finely divided resulting in theproduction of dense polyolefin. The degree of prepolymerization willhave a specific affect on catalytic properties. For example, in thelower ranges of prepolymerization the catalyst particle is disrupted andwill produce a smaller average particle size resin. In the higher range,the catalyst particle is increased in size and produces a larger averageparticle size resin.

Generally, the individual reaction steps can be conducted astemperatures in the range of about -50° C. to about 150° C. Preferredtemperature ranges are from about -30° C. to about 60° C. with -10° C.to about 50° C. being most preferred. The reaction time for theindividual treatment steps can range from about 5 minutes to about 24hours. However, lesser or greater times can be employed. Preferably thereaction time will be from about 1/2 hour to about 8 hours. During thereaction constant agitation is desirable.

In the preparation of the titanium containing catalyst component washingafter the completion of any step may be effected. However, it isgenerally found that the advantages of the catalyst system arediminished by washing after the last step. The catalyst componentprepared in accordance with this invention are usefully employed withthe cocatalyst well known in the art of the Ziegler catalysis forpolymerization of olefins.

Typically, the cocatalysts which are used together with the transitionmetal containing catalyst component are organometallic compounds ofGroup Ia, IIa, IIIa metals such as aluminum alkyls, aluminum alkylhydrides, lithium aluminum alkyls, zinc alkyls, magnesium alkyls and thelike. The cocatalysts desirably used are the organoaluminum compounds.The preferred alkylaluminum compounds are represented by the formulaAlR'"_(n) X"_(3-n) wherein R'" is hydrogen, hydrocarbyl or substitutedhydrocarbyl group and X" is halogen. Preferably R'" is an alkyl grouphaving from 2 to 8 carbon atoms. Illustrative examples of the cocatalystmaterial are ethyl aluminum dichloride, ethyl aluminum sesquichloride,diethyl aluminum chloride, aluminum triethyl, aluminum tributyl,diisobutyl aluminum hydride, diethyl aluminum ethoxide and the like.Aluminum trialkyl compounds are most preferred with triisobutylaluminumbeing highly desirable.

The catalyst system comprising the aluminum alkyl cocatalyst and thetransition metal containing catalyst component is usefully employed forthe polymerization of ethylene, other alpha-olefins having from 3 to 20carbon atoms, such as for example, propylene, butene-1, pentene-1,hexene-1, 4 methylpentene-1, and the like and ethylene copolymers withother alpha-olefins or diolefins such as 1,4-pentadiene, 1,5-hexadiene,butadiene, 2-methyl-1,3-butadiene and the like. The polymerizablemonomer of preference is ethylene. The catalyst may be usefully employedto produce polyethylene or copolymers of ethylene by copolymerizing withother alpha-olefins or diolefins, particularly propylene, butene-1,pentene-1, hexene-1, and octene-1 The olefins can be polymerized in thepresence of the catalyst of this invention by any suitable known processsuch as, for example, suspension, solution and gas-phase polymerizationprocesses.

The polymerization reaction employing catalytic amounts of theabove-described catalyst can be carried out under conditions well knownin the art of Ziegler polymerization, for example, in an inert diluentat a temperature in the range of 50° C. to 100° C. and a pressure of 2and 40 atmospheres, in the gas phase at a temperature range of 70° C. to100° C. at about 5 atmospheres and upward. Illustrative of the gas-phaseprocesses are those disclosed in U.S. Pat. No. 4,302,565 and U.S. Pat.No. 4,302,566 which references are incorporated by reference. Asindicated above, one advantageous property of the catalyst system ofthis invention is the reduced amount of gas phase reactor fouling. Thecatalyst system can also be used to polymerize olefins as a single-phaseconditions, i.e., 150° C. to 320° C. and 1,000-3,000 atmospheres. Atthese conditions the catalyst lifetime is short but the activitysufficiently high that removal of catalyst residues from the polymer isunnecessary. However, it is preferred that the polymerization be done atpressures ranging from 1 to 50 atmospheres, preferably 5 to 25atmospheres.

In the processes according to this invention it has been discovered thatthe catalyst system is highly responsive to hydrogen for the control ofmolecular weight. Other well known molecular weight controlling agentsand modifying agents, however, may be usefully employed.

The polyolefins prepared in accordance with this invention can beextruded, mechanically melted, cast or molded as desired. They can beused for plates, sheets, films and a variety of other objects.

While the invention is described in connection with the specificexamples below, it is understood that these are only for illustrativepurposes. Many alternatives, modifications and variations will beapparent to those skilled in the art in light of the below examples andsuch alternatives, modifications and variations fall within the generalscope of the claims.

In the Examples following the silica support was prepared by placingDavison Chemical Company G-952 silica gel in a vertical column andfluidizing with an upward flow of N2 The column was heated slowly to600° C. and held at that temperature for 12 hours after which the silicawas cooled to ambient temperature. The bulk density was determined byallowing the approximately 120 cc of resin to fall from the bottom of apolyethylene funnel across a gap of 1 inch into a tared 100 cc plasticcylinder (2.6 cm in diameter by 19.0 cm high). The funnel bottom wascovered with a piece of cardboard until the funnel was filled with thesample. The entire sample was then allowed to fall into the cylinder.Without agitating the sample, excess resin was scraped away so that thecontainer was completely filled without excess. The weight of resin inthe 100 cc cylinder was determined. This measurement was repeated 3times and the average value reported.

EXAMPLE 1 Catalyst Preparation

Into a vial containing 20 ml of hexane there was injected 10 ml ofbutylethylmagnesium (6.8 mmoles mg). To the solution was added 0.5 ml(6.8 mmoles) of n-butanol. The mixture was allowed to react at roomtemperature for 1.5 hours. The solution was added to a vial containing3.5 g of the Davison 952 silica and reacted with the silica for 1 hourat room temperature. To the reaction mixture was added 6.8 mmoles ofbenzoyl chloride with stirring. The reaction mixture was stirred at roomtemperature for 1 hour. To the slurry there was added 2.3 mmoles TiCl₄and the treatment was continued for 1 hour. Ethyl aluminum dichloride(EADC) (15.7 mmoles Al) was added and the reaction continued for 16hours. At one hour into the EADC reaction 10 ml (0.04 mmoles) ofethylene at atmospheric pressure was injected into the reaction vessel.The catalyst was in the form of a finely divided pink powder. Thecatalyst was filtered, washed 5 times with hexane and dried in vacuo.

Polymerization

To a 1.8 liter reactor there was added 800 cc of hexane, 0.075 g of theprepolymerized titanium containing solid catalyst component, triisobutylaluminum cocatalyst in an amount so as to provide an aluminum totitanium ratio of 50 mmoles. The vessel was pressured to 30 psig with H₂and thereafter pressured to 150 psig with ethylene. The vessel washeated to 85° C. and polymerization was maintained for 90 minutes. Theresults of the polymerization are summarized in Table 1. A secondpolymerization was conducted identically except that the polymerizationwas maintained for 40 minutes.

COMPARATIVE EXAMPLE 1 AND 2

A titanium containing catalyst component was prepared identically as inExample 1 with the exception that the prepolymerization step waseliminated.

Polymerization was maintained for 90 minutes and 40 minutes. The resultsof the polymerization are summarized in Table 1.

                  TABLE I                                                         ______________________________________                                                Specific                                                                      Activity  Bulk                                                                (Kg PE/g  Density   APS.sup.1                                                                           wt % Fines                                  Examples                                                                              Ti-hr-atm)                                                                              (lb/ft.sup.3)                                                                           (inch)                                                                              (less than 200)                             ______________________________________                                        1       19.0      25.5      0.010 1.40                                        2       19.0      22.0      --    --                                          Comp. 1 7.3       26.0      0.030 0.39                                        Comp. 2 11.6      17.4      0.020 0.91                                        ______________________________________                                         .sup.1 APS = average particle size                                       

What is claimed is:
 1. A transition metal containing solidprepolymerized catalyst component comprising the prepolymerized solidreaction product obtained by treating an inert solid support material inan inert solvent sequentially with (A) an organometallic compound of aGroup IIa, IIb or IIIa metal wherein all the metal valencies aresatisfied with a hydrocarbon group, (B) an oxygen containing compoundselected from ketones, aldehydes, alcohols or mixtures thereof, (C) anacyl halide, (D) at least one transition metal compound of a Group IVb,Vb, VIb or VIII metal , (E) a Group IIIa metal hydrocarbyl dihalide andprepolymerizing the solid with a minor amount of ethylene with theproviso that the inert solid support material can alternatively betreated with (i) the (A) organometallic compound and the (B) oxygencontaining compound simultaneously, (ii) the reaction product of the (A)organometallic compound and (B) oxygen containing compound or (iii) the(B) oxygen containing compound followed by treating with the (A)organometallic compound.
 2. The transition metal containing catalystcomponent of claim 1 wherein the (A) organometallic compound is adihydrocarbon magnesium compound represented by R¹ MgR² wherein R¹ andR² which can be the same or different are selected from alkyl groups,aryl groups, cycloalkyl groups, aralkyl groups, alkadienyl groups oralkenyl groups, the (B) oxygen containing compounds are selected fromalcohols and ketones represented by the formula R³ OH and wherein R³ andeach of R⁴ and R⁵ which may be the same or different can be an alkylgroup, aryl group, cycloalkyl group, aralkyl group, alkadienyl group oralkenyl group and the (C) acyl halide is represented by the formula R⁸COX wherein R⁸ can be an alkyl group, cycloalkyl group or aryl grouphaving from 1 to 12 carbon atoms and X is halogen and the Group IIIametal hydrocarbyl dihalide is one of alkyl boron dihalide, alkylaluminum dihalide or mixtures thereof.
 3. The transition metalcontaining catalyst component of claim 2 wherein the inert solid supportmaterial is one of silica, alumina, magnesia or mixtures thereof.
 4. Thetransition metal containing catalyst component of claim 2 wherein R¹,R², R³, R⁴, and R⁵ are alkyl groups having from 1 to 10 carbon atoms. 5.The transition metal containing catalyst component of claim 2 wherein R¹and R² are different.
 6. The transition metal containing catalystcomponent of claim 5 wherein R¹, R² and R³ are alkyl groups having from1 to 6 carbon atoms.
 7. The transition metal containing catalystcomponent of claim 6 wherein R¹ is butyl and R² is ethyl.
 8. Thetransition metal containing catalyst component of claim 2 wherein theGroup IIIa alkyl metal dihalide is one of ethyl boron dichloride orethyl aluminum dichloride.
 9. The transition metal containing catalystcomponent of claim 8 wherein the oxygen containing component is analcohol having from 1 to 4 carbon atoms.
 10. The transition metalcontaining catalyst component of claim 9 wherein R³ is butyl.
 11. Thetransition metal containing catalyst of claim 2 wherien R⁸ is an alkylgroup having from 1 to 6 carbon atoms or aphenyl having from 7 to 10carbon atoms and X is chlorine.
 12. The transition metal containingcatalyst of claim 11 wherein R⁸ is methyl or phenyl.
 13. The transitionmetal containing catalyst component of claim 2 wherein the transitionmetal compound or mixtures thereof is represented by the formulaTrX'_(4-q) (OR⁶)_(q), TrX'_(4-q) R_(q) ⁷, VOX'₃ or VO(OR⁶)₃ wherein Tris a transition metal, R⁶ is a hydrocarbyl group having from 1 to 20carbon atoms, R⁷ is an alkyl group, aryl group or aralkyl group havingfrom 1 to 20 carbon atoms or a 1,3-cyclopentadienyl, X' is halogen and qis 0 or a number equal to or less than
 4. 14. The transition metalcontaining catalyst component of claim 13 wherein Tr is titanium,vanadium or zirconium.
 15. The transition metal containing catalystcomponent of claim 14 whrein the transition metal compound is TiCl₄. 16.The transition metal containing catalyst component of claim 2 whereinthe organomagnesium compound and the oxygen containing compound arereacted together prior to contact with the inert support material. 17.The transition metal containing catalyst component of claim 16 whereinthe oxygen containing compound is an alkyl alcohol having from 1 to 4carbon atoms and the magnesium containing compound isethyl-n-butylamgesium.
 18. A catalyst system for the polymerization orcopolymerization of ethylene and alpha-olefins having from 3 to 12carbon atoms comprising (a) an organo aluminum compound of the formulaAlR"_(nX") _(3-n) wherein R"]is hydrogen or a hydrocarbon group havingfrom 1 to 20 carbon atoms, X is halogen and n is a number from 1 to 3,and (b) a transition metal containing solid prepolymerized catalystcomponent comprising the prepolymerized solid reaction product obtainedby treating an inert solid support material in an inert solventsequentially with (A) an organometallic compound of a Group IIa, IIb orIIIa metal wherein all the metal valencies are satisfied with ahydrocarbyl group, (B) an oxygen containing compound selected fromketones, aldehydes, alochols or mixtures thereof, (C) an acyl halide,(D) at least one transition metal compound of a Group IVb, Vb, VIb orVIII metal, (E) a Group IIIa metal hydrocarbyl dihalide andprepolymerizing the solid with a minor amount of ethylene with theproviso that the inert solid support material can alternatively betreated with (i) and (A) organometallic compound and the (B) oxygencontaining compound simultaneously, (ii) the reaction product of the (A)organometallic compound and (B) oxygen containing compound or (iii) the(B) oxygen containing compound followed by treating with the (A)organometallic compound.
 19. The catalyst system of claim 18 wherein the(A) organometallic compound is a dihydrocarbon magnesium compoundrepresented by R¹ MgR² wherein R¹ and R² which can be the same ordifferent are selected from alkyl groups, aryl groups, cycloalkylgroups, aralkyl groups, alkadienyl groups or alkenyl groups, the (B)oxygen containing compounds are selected from alcohols and ketonesrepresented by the formula R³ OH and R⁴ COR⁵ wherein R³ and each of R⁴and R⁵ which may be the same or different can be an alkyl group, arylgroup, cycloalkyl group, aralkyl group, alkadienyl group or alkenylgroup and the (C) acyl halide is represented by the formula R⁸ COXwherein R⁸ can be an alkyl group, cycloalkyl group or aryl group havingfrom 1 to 20 carbon atoms and X is halogen and the Group IIIahydrocarbyl dihalide is one of alkyl boron dihalide, alkyl aluminumdihalide or mixtures thereof.
 20. The catalyst system of claim 19wherein the inert solid support material is one of silica, alumina,magnesia or mixtures thereof.
 21. The catalyst system of claim 19wherein R¹, R², R³, R⁴, and R⁵ are alkyl groups having from 1 to 10carbon atoms.
 22. The catalyst system of claim 19 wherein R¹ and R² aredifferent.
 23. The catalyst system of claim 22 wherein R¹, R² and R³ arealkyl groups having from 1 to 6 carbon atoms.
 24. The catalyst system ofclaim 23 wherein R¹ is butyl and R² is ethyl.
 25. The catalyst system ofclaim 19 wherein the Group IIIa alkyl metal dihalide is one of ethylboron dichloride or ethyl aluminum dichloride.
 26. The catalyst systemof claim 25 wherein the oxygen containing component is an alcohol havingfrom 1-4 carbon atoms.
 27. The catalyst system of claim 26 wherein R³ isbutyl.
 28. The catalyst system of claim 19 wherein R⁸ is an alkyl grouphaving from 1 to 6 carbon atoms or a phenyl haivng from 7 to 10 carbonatoms and X is chlorine.
 29. The catalyst system of claim 28 wherein R⁸is methyl or phenyl.
 30. The catalyst system of claim 19 wherein thetransition metal compound or mixtures thereof is represented by theformula TrX'_(4-q) (OR⁶)_(q), TrX'_(4-q) R_(q) ⁷, VOX'₃ or VO(OR⁶)₃wherein Tr is a transition R⁶ is a hydrocarbyl group havin 1 to 20carbon atoms, R⁷ is an alkyl group, aryl group or aralkyl group havingfrom 1 to 20 carbon atoms or a 1,3-cyclopentadienyl, X' is halogen and qis 0 or a number equal to or less than
 4. 31. The catalyst system ofclaim 30 wherein Tr is titanium, vanadium or zirconium.
 32. The catalystsystem of claim 30 wherein the transition metal compound is TiCl₄. 33.The catalyst system of claim 19 wherein the organomagnesium compound andthe oxygen containing compound are reacted together prior to contactwith the inert support material.
 34. The catalyst system of claim 33wherein the oxygen containing compound is an alkyl alcohol having from 1to 4 carbon atoms and the magnesium containing compound isethyl-n-butylmagnesium.